Addressing the global sustainability challenge requires the action of all levels of government and of public and private actors. But local authorities, in particular, are key actors both in the design and the implementation of public policies. Due to the type of tasks they are responsible for (land planning, waste management, transport, etc.) they are in principle better equipped to attain substantial goals. And yet, in contexts of relatively low local autonomy and unsatisfactory coordination among levels of government, like the Spanish one, the functioning of local government to meet these goals can be inefficient. Drawing on survey and interview data from a representative sample of municipalities in the region of Madrid, this paper analyses how local governments actually face the challenge of sustainability and what are the problems they confront.